423 research outputs found
Protoptype integrated design (Pride) system reference manual. Volume 2: Schema definition
An initial description of an evolving relational database schema is presented for the management of finite element model design and analysis data. The report presents a description of each relation including attribute names, data types, and definitions. The format of this report is such that future modifications and enhancements may be easily incorporated
Comparison of in vitro and in situ plankton production determinations
Plankton production was measured using 8 techniques at 4 stations in the Celtic Sea, North Atlantic Ocean, in April 2002. Primary production (PP) was derived from 14C incorporation into particulate carbon after 24 h simulated in situ, PP(14CSIS), and 2 h photosynthesis-irradiance incubations, PP(14CPUR), and from 2 published satellite algorithms, PP(VGPM) and PP (M91). Gross production (GP) was calculated from O2 evolution, GP(O2), and 18O enrichment of dissolved O 2, GP(18O), after 24 h simulated in situ incubations, and from in situ active fluorescence measured by fast repetition rate fluorometry (FRRF). Net community production (NCP) was determined from changes in in situ dissolved oxygen, NCP(?O2), and from changes in oxygen during 24 h simulated in situ incubations, NCP(O2). Dark community respiration (DCR) was derived from changes in oxygen during a 24 h dark incubation, DCR(O2), and daily oxygen uptake, DOU(18O, O2), was calculated from the difference between GP(18O) and NCP(O2). Three stations were dominated by picoautotrophs and the fourth station was dominated by diatoms. While most of the comparisons between techniques fell within previously published ranges, 2 anomalies occurred only at the diatom-dominated station. Rates of PP(14CPUR) were oxygen uptake in the dark. The low rates of PP( 14CPUR) in relation to PP(14CSIS) may have resulted from the heterogeneous nature of the bloom and differences in sampling time. However, it is also possible that dissolved organic material (DOM) released by the stressed diatom population restricted the diffusion of 14C into the cells, thereby causing a greater underestimate of PP by techniques using short incubations. The significantly higher rates of oxygen uptake in the light are difficult to reconcile, and we do not know whether the light enhanced oxygen uptake was directly linked to carbon fixation. However, the release of DOM may also have provided substrate for enhanced respiration in the light. These anomalies were only revealed through the concurrent measurement of plankton production by this wide range of techniques. Further investigation of DOM excretion and light-enhanced respiration during diatom blooms is warranted
Bicyclic Boronates as Potent Inhibitors of AmpC, the Class C β-Lactamase from Escherichia coli
Resistance to β-lactam antibacterials, importantly via production of β-lactamases, threatens their widespread use. Bicyclic boronates show promise as clinically useful, dual-action inhibitors of both serine- (SBL) and metallo- (MBL) β-lactamases. In combination with cefepime, the bicyclic boronate taniborbactam is in phase 3 clinical trials for treatment of complicated urinary tract infections. We report kinetic and crystallographic studies on the inhibition of AmpC, the class C β-lactamase from Escherichia coli, by bicyclic boronates, including taniborbactam, with different C-3 side chains. The combined studies reveal that an acylamino side chain is not essential for potent AmpC inhibition by active site binding bicyclic boronates. The tricyclic form of taniborbactam was observed bound to the surface of crystalline AmpC, but not at the active site, where the bicyclic form was observed. Structural comparisons reveal insights into why active site binding of a tricyclic form has been observed with the NDM-1 MBL, but not with other studied β-lactamases. Together with reported studies on the structural basis of inhibition of class A, B and D β-lactamases, our data support the proposal that bicyclic boronates are broad-spectrum β-lactamase inhibitors that work by mimicking a high energy âtetrahedralâ intermediate. These results suggest further SAR guided development could improve the breadth of clinically useful β-lactamase inhibition
Toward an Integrative Multimodeling Interface: A Human-Computer Interface Approach to Interrelating Model Structures
Selective Phosphonylation of 5â˛-Adenosine Monophosphate (5â˛-AMP) via Pyrophosphite [PPi(III)]
We describe here experiments which demonstrate the selective phospho-transfer from a plausibly prebiotic condensed phosphorus (P) salt, pyrophosphite [H2P2O52â; PPi(III)], to the phosphate group of 5â˛-adenosine mono phosphate (5â˛-AMP). We show further that this P-transfer process is accelerated both by divalent metal ions (M2+) and by organic co-factors such as acetate (AcOâ). In this specific case of P-transfer from PPi(III) to 5â˛-AMP, we show a synergistic enhancement of transfer in the combined presence of M2+ & AcOâ. Isotopic labelling studies demonstrate that hydrolysis of the phosphonylated 5â˛-AMP, [P(III)P(V)-5â˛-AMP], proceeds via nuceophilic attack of water at the Pi(III) terminus
Faster, Better, Cheaper: Solutions to the Atmospheric Shipping Emission Compliance and Attribution Conundrum
Global concerns regarding air quality have over the past decade led to the introduction
of regulations by the International Maritime Organisation curbing the emissions of sulphur and
nitrogen oxides (SOx, NOx). These limits were implemented initially in so-called âemission control
areasâ, defined where the density of shipping activity combines with large coastal population centres
such as northwest Europe or eastern USA. However, any legislation requires a scientifically robust
and rigorous monitoring program to ensure compliance and prove attribution to an individual
vessel. We argue the case for adherence to the mantra âfaster, better, cheaperâ, where widespread
adoption of independent low-cost solutions of onboard, in-stack sensors, combined with existing,
globally ubiquitous satellite-based âautomatic identification systemâ (AIS) data telemetry, provides
an excellent solution to the affordable compliance and attribution conundrum for shipping companies
and enforcement agencies alike. We present data from three field-campaigns which have significantly
advanced the concept of onboard real-time monitoring of atmospheric ship emissions
Interaction of atopy and smoking on respiratory effects of occupational dust exposure: a general population-based study
BACKGROUND: For individual exposures, effect modification by atopy or smoking has been reported on the occurrence of occupational airway disease. It is unclear if effect modification can be studied in a general population by an aggregated exposure measure. Assess relationship between airway obstruction and occupational exposure using a job-exposure-matrix (JEM) classifying jobs into 3 broad types of exposure, and test for effect modification by atopy, and smoking. METHODS: Data from 1,906 subjects were analyzed, all participants of the European Community Respiratory Health Survey. Job titles were categorized by an a priori constructed job exposure matrix into three classes of exposure to respectively organic dust, mineral dust, and gases/ fumes. Relationships were assessed for 'current wheeze', bronchial hyperresponsiveness (BHR), 'current asthma' (wheeze+BHR), and 'chronic bronchitis' (morning phlegm or morning cough), and lung function. RESULTS: Subjects with organic dust exposure in their work environment more frequently had 'current asthma' (OR 1.48, 95% C.I. 0.95;2.30), and a lower FEV(1 )(-59 mL, 95% C.I. -114;-4). The relationship was only present in asthmatic workers, and their risk was four-fold greater than in subjects with either atopy or exposure alone. Mineral dust exposure was associated with 'chronic bronchitis' (OR 2.22, 95% C.I. 1.16;4.23) and a lower FEV(1)/FVC ratio (-1.1%, 95% C.I. -1.8;-0.3). We observed an excess risk in smokers, greater than the separate effects of smoking or mineral dust exposure together. CONCLUSION: Occupational exposure to organic dust is associated with an increased risk of asthma, particularly in atopics. Chronic bronchitis occurs more frequently among individuals exposed to mineral dust, and smoking doubles this risk
A qualitative evidence synthesis of employees' views of workplace smoking reduction or cessation interventions
Background
The need to reduce smoking rates is a recognised public health policy issue in many countries. The workplace offers a potential context for offering smokersâ programmes and interventions to assist smoking cessation or reduction. A qualitative evidence synthesis of employeesâ views about such programmes might explain why some interventions appear effective and others not, and can be used to develop evidence-based interventions for this population and setting.
Methods
A qualitative evidence synthesis of primary research exploring employeesâ views about workplace interventions to encourage smoking cessation, including both voluntary programmes and passive interventions, such as restrictions or bans. The method used was theory-based âbest fitâ framework synthesis.
Results
Five relevant theories on workplace smoking cessation were identified and used as the basis for an a priori framework. A comprehensive literature search, including interrogation of eight databases, retrieved 747 unique citations for the review. Fifteen primary research studies of qualitative evidence were found to satisfy the inclusion criteria. The synthesis produced an evidence-based conceptual model explaining employeesâ experiences of, and preferences regarding, workplace smoking interventions.
Conclusion
The synthesis suggests that workplace interventions should employ a range of different elements if they are to prove effective in reducing smoking among employees. This is because an employee who feels ready and able to change their behaviour has different needs and preferences from an employee who is not at that stage. Only a multi-faceted intervention can satisfy the requirements of all employees
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